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Abstract:

The disclosed device controls a cable associated with a bicycle gearshift
and is particularity configured for securing the body of the device on
the forward-facing end of racing bicycle handlebars. A cable winding
bobbin, having an internally toothed crown, is provided in the device's
body and a drive mechanism rotates the bobbin in the chosen direction to
achieve predetermined angular positions. A ratchet mechanism, located
between the lever and the toothed crown, includes opposite rocker arms
with cam profiles curved away from each other, and a toothed sector for
engaging the toothed crown. A pointer is located to be selectively
engaged with at least one of the rocker arms so that engagement results
in the rocker arm's toothed section being away from the toothed crown,
and disengagement results in the rocker arm's toothed section being
engaged with the toothed crown.

Claims:

1. Actuation device (100) for a control cable (K) for a bicycle
gearshift, comprising: a casing (101), configured for attachment on the
end (MS) of handlebars of the bicycle, a bobbin (112) on which to wind
the cable (K), angularly mobile in the casing (101) around a main axis
(A) of the device (100), a drive mechanism (130), acting on the bobbin
(112) to rotate it in a first and in a second angular direction (104,
105) around the main axis (A) of the device (100), indexing means (113)
to removably hold the bobbin (112) in predetermined angular positions, in
which the drive mechanism (130) comprises: a lever (131), angularly
mobile with respect to the casing (101) around the main axis (A) of the
device (100), in the first or in the second angular direction (104, 105)
from a neutral position to obtain downward or upward gearshifting, an
internally toothed crown (114), non-rotatably mounted to the bobbin (112)
and with it angularly mobile in the casing (101), a ratchet mechanism
(140) between the lever (131) and the toothed crown (114), characterised
by comprising elastic means (133) acting between the lever (131) and the
casing (101), which tend to bring the lever (131) back into the neutral
position, and in that the ratchet mechanism (140) comprises: two opposite
rocker arms (141, 142), hinged on the lever (131) according to two pivot
axes (B, C) parallel to one another and to the main axis (A) of the
device (100), each of said rocker arms (141, 142) having an arched
shape--wrapping around the main axis (A) of the device (100)--extending
from a first (143, 145) to a second (144, 146) end, in which the first
end (143) of the first rocker arm (141) is close to the first end (144)
of the second rocker arm (142) and the second end (145) of the first
rocker arm (141) faces towards the second end (146) of the second rocker
arm (142), a toothed sector (147, 148), formed on each rocker arm (141,
142) on an outer side thereof, close to the second end (145, 146), said
sector having a toothing profile suitable for engaging with the toothing
of the toothed crown (114), which crown is in an axial position
corresponding to that of the toothed sectors (147, 148) along the main
axis (A) of the device (100), a cam profile (151, 152), formed on each
rocker arm (141, 142) on an inner side thereof, adjacent to the first end
(143, 144), a thruster (161), to thrust each rocker arm (141, 142) around
its pivot axis (B, C) in the direction to thrust the second ends (145,
146) of the rocker arms (141, 142) away from the main axis (A) of the
device (100), a pointer (160), stationary with respect to the casing
(101) and facing radially outwards with respect to the main axis (A) of
the device (100), engaged with at least one of the rocker arms (141,
142), on its cam profile (151, 152), in which the cam profile (151, 152)
is configured so that: when the pointer (160) is engaged with the cam
profile (151, 152) of a rocker arm (141, 142), the toothed sector (147,
148) of the same rocker arm (141, 142) is held away from the toothed
crown (114), when the pointer (160) is disengaged from the cam profile
(151, 152), the toothed sector (147, 148) of the same rocker arm (141,
142) is thrusted into engagement with the toothed crown (114) by the
thruster (161).

2. Device according to claim 1, wherein the thruster (161) is a spring
compressed between the second ends (145, 146) of the two rocker arms
(141, 142).

3. Device according to claim 1, wherein in the neutral position the
pointer (160) is engaged with a first portion (155, 156) of the cam
profile (151, 152) of both of the rocker arms (141, 142).

4. Device according to claim 3, wherein the elastic means comprise a
spring (133) acting between the casing (101) and the lever (131), to take
the lever (131) into its neutral angular position.

5. Device according to claim 1, wherein each of the rocker arms (141,
142) is hinged to the lever (131) by means of a respective pin (134,
135).

6. Device according to claim 1, wherein the pivot axis (B, C) of each
rocker arm (141, 142) is positioned closer to the first (143, 144) than
to the second (145, 146) end of the rocker arm (141, 142).

7. Device according to claim 1, wherein the toothing profile of the
toothed sector (147, 148) and of the toothed crown (114) are such as to
promote snap disengagement, one tooth at a time, when the sector (147,
148) moves with the lever (131) going back into its neutral angular
position while the toothed crown (114) stays still.

8. Device according to claim 7, wherein the toothing profile of the
toothed sector (147, 148) comprises teeth (157, 158) with a thrusting
side (157a, 158a) facing towards the second end (145, 146) of the rocker
arm (141, 142) and a release side (157b, 158b) facing the opposite way,
in which the thrusting side (157a, 158a) is oriented--with reference to a
cross section with respect to the main axis (A) of the device (100)--so
that a half-line (D1) tangent to the thrusting side (157a, 158a) and
oriented towards the outside of the device (100) forms an angle (a)
greater than or equal to 90.degree. with a half-line (D2) that from the
thrusting side (157a, 158a) points towards the pivot axis (B, C) of the
rocker arm (141, 142).

9. A device for controlling a cable (K) associated with a bicycle
gearshift comprising: a casing (101) configured for attachment on an end
(MS) of bicycle handlebars to secure the body of the device; a cable
winding bobbin (112) mounted within the casing (101) and having an
internally toothed crown (114); an indexer (113) that holds the bobbin
(112) in a predetermined angular position; a drive mechanism (130) that
includes a lever (131) that is actionable from a neutral position to
obtain downward or upward gearshifting and rotates the bobbin (112) to
achieve the predetermined angular position; a ratchet mechanism (140),
located between the lever (131) and the toothed crown (114), that
includes opposite rocker arms (141, 142) that arched cams with profiles
that curve away from each other, and a respective toothed sector (147,
148) for engaging with the toothed crown (114); a pointer (160) that is
stationary with respect to the casing 101) and is located so that it can
selectively engaged by at least one of the rocker arms; a thruster (161)
that urges the rocker arms toward the neutral position with respect to
the pointer; and, whereby engagement between a respective cam profile and
the pointer results in that rocker arm's toothed section being moved away
from the toothed crown (114), and the opposed rocker arm's toothed
section being moved toward engagement with the toothed crown.

Description:

BACKGROUND

[0001] The present invention concerns an actuation device for a control
cable for a bicycle gearshift, in particular a so-called bar-end device
suitable for being mounted on the forward-facing end of racing bicycle
handlebars.

[0002] A bicycle is normally provided with a rear derailleur associated
with the chainset, which consists of a series of coaxial gear wheels
(pinions), having different diameters and numbers of teeth, fixedly
connected to the hub of the rear wheel.

[0003] A bicycle is typically also provided with a front derailleur
associated with the crankset, which consists of a series of gear wheels
(toothed crowns) having different diameters and numbers of teeth,
associated with a pin of the bottom bracket assembly set in rotation by a
pair of pedals.

[0004] In both cases, the derailleur engages a transmission chain
extending in a closed loop between the chainset and the crankset,
shifting the chain on gear wheels having different diameters and numbers
of teeth, so as to obtain different transmission ratios.

[0005] In particular, the expression downward gearshifting is used when
the chain goes from a gear wheel having a larger diameter to a gear wheel
having a smaller diameter, and the expression upward gearshifting when
the chain moves from a gear wheel having a smaller diameter to a gear
wheel having a greater diameter. Regarding this, it should be noted with
reference to the front derailleur that downward gearshifting corresponds
to passing to a lower transmission ratio and upward gearshifting
corresponds to passing to a higher transmission ratio, vice-versa with
reference to the rear derailleur, downward gearshifting corresponds to
passing to a higher transmission ratio and upward gearshifting
corresponds to passing to a lower transmission ratio.

[0006] The movement in the two directions of a derailleur is obtained
through an actuation device mounted so as to be easily operated by the
cyclist; in the case of a so-called bar-end device, mounting takes place
on the handlebars, at the ends thereof.

[0007] Conventionally, the actuation device for the front derailleur is
located on the left handgrip of the handlebars, and vice-versa the
actuation device for the rear derailleur is located on the right
handgrip.

[0008] More specifically, in a mechanical gearshift, each derailleur is
moved between the gear wheels, in a first direction by a pulling action
exerted by a normally sheathed inextensible cable (commonly called Bowden
cable), and in a second opposite direction by releasing the traction on
the cable and/or by the elastic return action of a spring provided in the
derailleur itself.

[0009] Normally, the direction in which the movement is caused by the
release of the traction of the cable and/or by the return spring is that
of downward gearshifting; vice-versa, the pulling action of the control
cable takes place in the direction of upward gearshifting, in which the
chain moves from a wheel having a smaller diameter to a wheel having a
greater diameter.

[0010] In the actuation device, the control cable is actuated in traction
or in release through winding and unwinding on a rotor element, commonly
called cable-winding bobbin, the rotation of which is controlled by the
cyclist with a suitable control lever. Single-lever control is made
necessary by the positioning at the end of the handlebars, where it would
be complex and not very practical to use two control levers, as it
occurs--on the other hand--for different types of devices, located in
different parts of the handlebars.

[0011] In any case, the actuation device must ensure that the bobbin is
held still in rotation in a number of predetermined angular positions,
corresponding to the different positions of the derailleur required by
the different ratios, i.e. on the different gear wheels of the gearshift.
This function is obtained with so-called indexers, a great many types of
which are known in the field, variously acting between the bobbin and the
fixed casing of the device.

[0012] In more conventional so-called bar-end devices, the single-lever
control acts substantially directly on the cable-winding bobbin, so that
each angular position of the cable-winding bobbin, as defined by the
indexing means, corresponds to a precise angular position of the control
lever.

[0013] The search for better aerodynamics in a competition has led to the
provision of a quite complex control device, described in EP-1837275-A2,
which is intended to return into the neutral position. It is the purpose
of the present invention to provide a simplified device that allows the
return of the control lever into its neutral position.

BRIEF DESCRIPTION OF THE DRAWINGS

[0014] The features and advantages of the invention will fully understood
from the description of preferred embodiments with reference to the
attached drawings.

[0015]FIG. 1 is a perspective view of a device according to the
invention;

[0016] FIGS. 2 and 3 are exploded perspective views of the device of FIG.
1;

[0021] The present invention provides a device for controlling a cable
associated with a bicycle gearshift. The device has a casing configured
for attachment on the end of bicycle handlebars to secure the body of the
device. A cable winding bobbin, having an internally toothed crown, is
provided in the device's body and a drive mechanism rotates the bobbin in
the chosen direction to achieve predetermined angular positions. The
drive mechanism includes a lever that is actionable from a neutral
position to obtain downward or upward gearshifting is biased toward the
neutral position. A ratchet mechanism, located between the lever and the
toothed crown, includes opposite rocker arms that pivot parallel axes
that are also parallel to the main axis. Each rocker arm has an arched
shape cam, such that the arches of the cam profiles curve away from each
other, and includes a toothed sector for engaging with the toothed crown.
A pointer, that is stationary with respect to the casing, is located to
be engaged with at least one of the rocker arms so that it can be engaged
and disengaged with a respective cam. A thruster urges the rocker arms
toward the neutral position of the pointer whereby engagement of the
pointer with a respective cam profile results in the rocker arm's toothed
section being away from the toothed crown, and disengagement of the
pointer with a respective cam profile results in the rocker arm's toothed
section being engaged with the toothed crown.

[0022] This device allows the desired operation in which the lever can go
back into its neutral position at the end of gearshifting. Indeed, the
lever is not directly fixedly connected to the bobbin (or to the toothed
crown, non-rotatably mounted to the bobbin), but the ratchet mechanism is
arranged between them, which keeps the lever released from the toothed
crown with the exception of the moment when gearshifting is commanded. At
that moment, according to whether it is downward or upward gearshifting,
the angular movement of the lever in one direction or in the other causes
a movement of the rocker arms on the lever itself such that one or the
other of the two rocker arms is moved on the lever until its toothed
sector is taken into engagement with the toothed crown; in this way, the
angular movement of the lever is transmitted to the toothed crown and to
the cable-winding bobbin. Once the action on the lever by the cyclist has
ended, the cable-winding bobbin and the toothed crown are held by the
indexing means in the position reached, whereas the lever tends to go
back into the neutral position under the action of the elastic means,
without the ratchet mechanism opposing it.

[0023] Preferably, the thruster is a spring compressed between the second
ends of the two rocker arms. Indeed, since the two rocker arms work in
opposition to one another, it is sufficient to have a spring suitably
arranged between the two rocker arms to generate the desired thrust on
each of them, without it thus being necessary to have a spring for each
of them.

[0024] Preferably, in the neutral position the pointer is engaged with a
first portion of the cam profile of both of the rocker arms. In this way,
the neutral position--reached thanks to the action of the elastic
means--is safely maintained since the engagement of the pointer with both
of the cam profiles ensures that neither of the two toothed sectors can
go into engagement with the toothed crown.

[0025] Preferably, the elastic means comprise a spring acting between the
casing and the lever, to take the lever into its neutral angular
position. Such a spring can be a simple ring-shaped torsion spring,
mounted in the casing coaxially to the main axis (A) of the device and
fixedly connected at one end to the casing, at the other to the lever.

[0026] Preferably, each of the rocker arms is hinged to the lever by means
of a respective pin, formed on the lever, on the rocker arm or
structurally independent.

[0027] Preferably, the pivot axis of each rocker arm is closer to the
first than to the second end of the rocker arm. Maximising the distance
between the pivot axis and the toothed sector, which is close to the
second end of the rocker arm, allows the thrusting direction of the
rocker arm on the toothed sector when the latter is engaged with the
toothed crown to be almost the same for all the single teeth of the
toothed sector; all of the teeth of the toothed sector thus participate
in a substantially equal manner to the thrust. This allows efficient
sizing of the toothed sector, which is important since the device must be
as light as possible, given its use on racing bicycles.

[0028] Preferably, the toothing profile of the toothed sector and of the
toothed crown are such as to promote the snap disengagement, one tooth at
a time, when the sector moves with the lever going back into its neutral
angular position while the toothed crown stays still.

[0029] More specifically, the toothing profile of the toothed sector
comprises teeth with a thrusting side facing towards the second end of
the rocker arm and a release side facing the opposite way, in which the
thrusting side is oriented--with reference to a cross section with
respect to the main axis (A) of the device--so that a half-line tangent
to the thrusting side and oriented towards the outside of the device
forms an angle equal to or greater than 90° with a half-line that
from the thrusting side points towards the pivot axis of the rocker arm.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0030] The figures show an actuation device 100 for the control cable K of
a front gearshift of a racing bicycle (not shown). With particular
reference to FIG. 1, the device 100 is a so-called bar-end device,
mounted at the left end MS of bicycle handlebars of the type used on
racing bicycles, and even more specifically specialised bicycles for time
trial racing; in such handlebars, the end MS faces forwards, with respect
to the direction of forward motion of the bicycle.

[0031] The device 100 comprises a casing 101, which is fixed to the
handlebars M in a conventional manner, so as to itself be a substantial
forward extension of the end MS of the handlebars. The casing 101
comprises a body 110 and a cover 120, fixedly connected to one another
through two threaded elements 102 and 103, extending along an axis A. The
axis A--as will be made clearer hereafter--is the main reference axis for
the elements that form part of the device 100; all indications of
directions and the like, such as "axial", "radial", "circumferential" and
"diametral", will be made with reference to it; likewise, the indications
"outwards" and "inwards" referring to radial directions must be taken as
away from the axis A or towards the axis A. Around the axis A, two
opposite angular directions are also defined, indicated with 104 and 105,
the first in the clockwise direction, the second in the anti-clockwise
direction, observing the device 100 as represented in FIGS. 3 and 6-17.

[0032] In the casing 101, there is a central pin 111, fixed with respect
to the body 110 of the casing 101 and extending along the axis A.

[0033] On the pin 111, a cable-winding bobbin 112 is mounted free in
rotation; the cable K to be actuated is fixed thereto and wound thereon.
The bobbin 112 is connected to the casing 101 by an indexing assembly
113, to hold the bobbin 112 in predetermined angular positions with
respect to the casing 101, according to the selected ratio of the
gearshift. Such an assembly is per se conventional and is not part of the
present invention; therefore, it will not be described in detail
hereafter.

[0034] A counter-pin 116, mounted on the pin 111 on an axially opposite
side of the bobbin 112, completes the rotary assembly of the bobbin 112
in the casing 101.

[0035] In the casing 101 there is also a central tang 121, fixed with
respect to the cover 120 of the casing 101 and extending along the axis
A. An annular element 122 is mounted on the tang 121--non-rotatably fixed
thereto.

[0036] The device 100 also comprises a drive mechanism, to obtain downward
or upward gearshifting, generally indicated with 130, acting on the
bobbin 112 to rotate it in the angular directions 104 and 105 around the
axis A.

[0037] The drive mechanism 130 comprises an internally toothed crown 114,
non-rotatably mounted to the bobbin 112, and a lever 131, that can be
actuated by the cyclist and is angularly mobile with respect to the
casing 101 around the axis A, in the angular directions 104 and 105 from
a neutral position (shown in FIGS. 1, 4, 5, 6, 12, 18). The lever 131 is
rotatably supported by means of a bush 132 mounted on the tang 121, at
the side of the annular element 122, and elastic means (in particular a
spring 133) acting between the casing 101 and the lever 131, to take the
lever 131 into its neutral angular position.

[0038] The drive mechanism also comprises a ratchet mechanism 140 between
the lever 131 and the toothed crown 114.

[0039] The ratchet mechanism 140 comprises two opposite and symmetrically
identical rocker arms 141 and 142, hinged on an side of the lever 131
through two pins 134, 135 arranged according to pivot axes B and C that
are parallel to one another and to the main axis A of the device 100.
Each of the rocker arms 141 and 142 has an arched shape, wrapping around
the axis A, extending from a first end 143, 144 to a second end 145, 146;
the first end 143 of the first rocker arm 141 is close to the first end
144 of the second rocker arm 142, whereas the second end 145 of the first
rocker arm 141 faces towards the second end 146 of the second rocker arm
142, spaced from it in the substantially tangential direction with
respect to the axis A.

[0040] On each rocker arm 141, 142, a respective toothed sector 147, 148
is formed, formed on an outer side of the rocker arm 141, 142, close to
the second end 145, 146. The toothed sector 147, 148 has a toothing
profile suitable for engagement with the toothing of the toothed crown
114. The toothed crown 114 and the rocker arms 141, 142 are substantially
in the same axial position along the axis A, and therefore the toothed
crown 114 is in a position in front of the toothed sectors 147, 148.

[0041] Again on each rocker arm 141, 142, a respective cam profile 151,
152 is formed, formed on an inner side of the rocker arm 141, 142,
adjacent to the first end 143, 144. The cam profile 151, 152 comprises a
main portion 153, 154 extending substantially in the circumferential
direction around the axis A, preceded by a greatly inclined short first
portion 155, 156, adjacent to the first end 143, 144 of the rocker arm
141, 142.

[0042] The cam profiles 151, 152 are in contact engagement--according to
the operating steps, which will be discussed later--with a pointer 160,
formed from an outer projection on the annular element 122, see FIGS. 2
and 6, extending parallel to the axis A; the pointer 160 is stationary
with respect to the casing 101 and faces radially outwards with respect
to the axis A.

[0043] The ratchet mechanism 140 also comprises a thruster 161, to thrust
each rocker arm 141, 142 around its pivot axis B, C, in the direction to
push the second ends 145, 146 of the rocker arms 141, 142 away from the
axis A. Preferably, the thruster 161 is a spring, compressed between the
second ends 145, 146 of the rocker arms 141, 142.

[0044] Each cam profile 151, 152 is configured so that: [0045] when the
pointer 160 is engaged with the cam profile 151, 152 of a rocker arm 141,
142, the toothed sector 147, 148 of the same rocker arm is kept away from
the toothed crown 114; [0046] when the pointer 160 is disengaged from the
cam profile 151, 152 of a rocker arm 141, 142, the toothed sector 147,
148 of the same rocker arm is thrusted into engagement with the toothed
crown 114 by the thruster 161.

[0047] Given the proximity of the first ends 143, 144 of the rocker arms
141, 142, the pointer 160 is always engaged with at least one of the
rocker arms 141, 142, on its cam profile 151, 152; in the neutral
position of the lever 131, the pointer 160 is engaged with the first
portion 155, 156 of the cam profiles 151, 152 of both of the rocker arms
141, 142.

[0048] The rocker arms 141, 142 are shaped and sized so that the pivot
axis B, C of each rocker arm 141, 142 is closer to the first end 143, 144
than to the second end 145, 146 of the rocker arm itself.

[0049] The toothing profile of the toothed sector 147, 148 and of the
toothed crown 114 are such as to promote the snap disengagement, one
tooth at a time, when the toothed sector 147, 148 moves with the lever
131 going back into its neutral position while the toothed crown 114
stays still.

[0050] More specifically, the toothing profile of the toothed sector 147,
148 comprises teeth 157, 158 with a thrusting side 157a, 158a facing
towards the second end 145, 146 of the rocker arm 141, 142 and a release
side 157b, 158b facing the opposite way. The thrusting side 157a, 158a is
oriented--with reference to a cross section with respect to the axis
A--so that a half-line D1 tangent to the thrusting side 157a, 158a and
oriented towards the outside of the device 100 forms an angle α
equal to or greater than 90° with a half-line D2 that from the
thrusting side 157a, 158a points towards the pivot axis B, C of the
rocker arm 141, 142.

[0051] The operation of the device 100 will now be described with
reference in particular to FIGS. 6-18; it should be noted that every
angular movement of the toothed crown 114 corresponds to an identical
angular movement of the cable-winding bobbin 112 and thus to a
gearshifting.

[0052]FIG. 6 shows the neutral position of the lever 131, which
corresponds to a non-gearshifting situation, with the gearshift having a
certain ratio and keeping it. In this position, as already stated, the
pointer 160 is engaged with the first portion 155, 156 of the cam
profiles 151, 152 of both of the rocker arms 141, 142. No toothed sector
147, 148 is engaged with the toothed crown 114.

[0053] From this position, the lever 131 is moved by the cyclist in the
direction 105. As shown in FIG. 7, as soon as the lever 131 has reached a
minimum angular movement, the pointer 160 disengages from the cam profile
152 of the rocker arm 142, which is thus thrusted by the thruster 161
with the toothed sector 148 towards the toothed crown 114.

[0054] As the movement of the lever 131 proceeds, as shown in FIGS. 8 and
9, the engagement of the toothed sector 148 with the toothed crown 114
ensures that the toothed crown moves angularly together with the lever
131. This movement will thus be continued by the cyclist until the
angular position corresponding to the gearshifting that is wanted is
reached; indeed, it is possible to move the lever 131 by a small angle to
obtain single gearshifting (going to an immediately greater or smaller
ratio), as well as by a greater angle, corresponding to multiple
gearshifting (double, triple or even more).

[0055] Once the desired angular position has thus been reached, the
cyclist interrupts the thrust on the lever 131 and leaves it. While the
toothed crown 114 is kept still in the angular position reached by the
indexing assembly 113, the lever 131 that has been left free tends to be
brought back towards its neutral position by the action of the spring 133
(FIG. 10); the lever 131 thus starts to move in the angular direction
104. Given the geometry of the teeth 158 and of the rocker arm 142, and
also given the non-engagement of the pointer 160 in the cam profile 152,
the rocker arm 142 can rotate in the anti-clockwise direction around the
pivot axis C (overcoming just the elastic force of the thruster 161),
thus disengaging its toothed sector 148 from the toothed crown 114 (FIG.
11). In practice, the toothed sector 148 rides over the teeth of the
toothed crown one by one, until the lever 131 goes back into the neutral
position (FIG. 12).

[0056] Eventually, gearshifting has been carried out, single or multiple,
and at the end the lever 131 is back into its neutral starting position,
ready for more gearshifting, in the same or other direction. FIGS. 13 to
18, similarly to FIGS. 7-12, show gearshifting in the opposite direction;
given the total symmetry of operation, these steps will not be described.

[0057] Of course, a man skilled in the art can bring modifications and
variants to what has been described, without departing from the scope of
protection defined by the following claims.

Patent applications by Giuseppe Dal Prá, Zane IT

Patent applications by CAMPAGNOLO S.R.L.

Patent applications in class Single rotatable lever (e.g., for bicycle brake or derailleur)

Patent applications in all subclasses Single rotatable lever (e.g., for bicycle brake or derailleur)